NextBillion - An Initiative of the William Davidson Institute at the University of Michigan

Tuesday, December 2, 2014

“It only takes one virus to get through for a person to be infected,” explained Dr. John Mascola. This is true of any viral infection, but in this instance, Mascola is referring to HIV and his ongoing efforts to develop a vaccine against the virus. “It’s been so difficult to make an HIV/AIDS vaccine.”

Those were the words of many working in HIV vaccine development until the results of a 2009 trial in Thailand surprised everyone. “The field is energized,” said Mascola, director of the Vaccine Research Center at the U.S. National Institute of Allergy and Infectious Diseases, describing the change in atmosphere in the vaccine community.

The trial included over 16,000 volunteers and was the largest clinical trial ever conducted for a vaccine against HIV. It was also the first to show any protection at all against infection.

Two previously developed vaccines, known as ALVAC-HIV and AIDSVAX, were used in combination, with the first priming an immune response against HIV and the second used as a booster once the immunity waned. The duo reduced the risk of contracting HIV by 31.2% — a modest reduction, but it was a start.

To date, only four vaccines have made it as far as testing for efficacy to identify their levels of protection against HIV. Only this one showed any protection.